Multi cascade cooling system

ABSTRACT

A multi cascade cooling system is disclosed, having a refrigerant flowing in refrigerating components, that comprises at least one first heat-exchanger configured to receive the refrigerant from a component of the refrigerating components and cooling it with a first fluid provided by a sorption machine and at least one second heat-exchanger configured to receive the refrigerant from the at least one first heat-exchanger and regulate a temperature of the refrigerant with a second fluid provided by an auxiliary cooler. The refrigerant flows from the at least one second heat- exchanger to another component of the refrigerating components.

TECHNICAL FIELD

The present disclosed subject matter relates to refrigeration in general. More particularly, the present disclosed subject matter relates to energy efficiency improvement of cooling systems.

BACKGROUND

Commercially available cascade apparatus typically consists of one or more single-circuit refrigerating apparatuses where each apparatus comprises a compressor, evaporator, condenser, expansion valve and heat-exchangers. Typically, a cascade apparatus represents a two-circuit refrigerating apparatus, thus different refrigerants power per cascade. Heat pumps can function in cascade cycles with various refrigerants, such as an air-precooling-type apparatus, utilizing air as a heat carrier while the primary cooling circuit includes a compressor, a condenser, evaporator and triple-stream heat exchanger. Such commercially available cascade apparatus employs auxiliary compressor, condenser and evaporator that that can be connected to the triple-stream heat exchanger.

The use of two or more electric driven compressors is usual within the existing cascade refrigerating apparatuses. Low-temperature cascade refrigerating apparatuses operate with the input electric power that is 30-40% higher than the output refrigerating.

In other commercially available systems, a refrigerating apparatus can comprise both compression and absorption circuits. The absorption circuit can comprise an engine or a prime electric generator combination. A driver thereof supplies the generator of the absorption circuit with heat energy, and the electric drive of the refrigerating circuit with electric energy. This way of coupling of a refrigerating compressor with an absorption circuit does not allow classifying the above refrigerating apparatus as a cascade one. On the other hand, it may well be classified as a hybrid apparatus, wherein the compressor supplies the refrigerant vapor to the condenser or the medium heat-exchanger.

BRIEF SUMMARY

According to a first aspect of the present disclosed subject matter, A multi cascade cooling system, having a refrigerant flowing in refrigerating components, the system comprising:

-   -   at least one first heat-exchanger configured to receive the         refrigerant from a component of the refrigerating components and         cooling it with a first fluid provided by a sorption machine;     -   at least one second heat-exchanger configured to receive the         refrigerant from the at least one first heat-exchanger and         regulate a temperature of the refrigerant with a second fluid         provided by an auxiliary cooler; and     -   wherein the refrigerant flows from the at least one second         heat-exchanger to another component of the refrigerating         components.

In some exemplary embodiments, the at least one first heat-exchanger and the at least one second heat-exchanger are integrated into at least one twofold heat-exchanger, and wherein the refrigerant is cooled by the first fluid and regulated by the second fluid in the at least one twofold heat-exchanger simultaneously.

In some exemplary embodiments, the at least one second heat-exchanger is configured to regulate a temperature of the first fluid with the second fluid; and wherein the at least one first heat-exchanger is configured to receive the first fluid from the at least one second heat-exchanger for cooling the refrigerant, and wherein the refrigerant flows from the at least one first heat-exchanger to the another component of the refrigerating components.

In some exemplary embodiments, the at least one second heat-exchanger is configured to cool the second fluid with the first fluid, wherein the at least one first heat-exchanger is configured to receive a cooled second fluid from the at least one second heat-exchanger for cooling the refrigerant, and wherein the refrigerant flows from the at least one first heat-exchanger to the another component of the refrigerating components.

In some exemplary embodiments, the sorption machine is selected from a group consisting of absorption machine; adsorption machine; and any combination thereof.

In some exemplary embodiments, the sorption machine is primarily powered by residual energy is selected from a group consisting of gray water; steam; exhaust gas, hot water; and any combination thereof.

In some exemplary embodiments, the second fluid is adopted to regulate the temperature of the refrigerant due to inconsistent temperature of the first fluid resulting from volatility of residual energy.

In some exemplary embodiments, the component is a condenser and the another component is an expansion-valve.

In some exemplary embodiments, the refrigerant is selected from a group consisting of R22; R410A; R12; R134; and any combination thereof.

In some exemplary embodiments, the first fluid and the second fluid are selected from a group consisting of water; R22; R410A; R12; R134; and any combination thereof.

According to another aspect of the present disclosed subject matter, a method of operation of the multi cascade cooling system is provided, the method comprising:

-   -   receiving the refrigerant from the component;     -   cooling the refrigerant with the first fluid;     -   regulating the temperature of the refrigerant with the second         fluid; and     -   flowing the refrigerant to the another component.

In some exemplary embodiments, said regulating the temperature is regulating the temperature of the first fluid with the second fluid.

In some exemplary embodiments, said cooling the refrigerant is cooling and regulating the temperature of the refrigerant with the second fluid and wherein the first fluid is cooling the second cooling.

In some exemplary embodiments, the multi cascade cooling system is installed in a transportation vehicle.

In some exemplary embodiments, the sorption machine is powered by residual energy that is selected from a group consisting of radiator fluid of the vehicle engine, oil of the vehicle engine, exhaust fumes; and any combination thereof.

In some exemplary embodiments, the auxiliary cooler is powered by auxiliary batteries.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosed subject matter belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosed subject matter, suitable methods and materials are described below. In case of conflict, the specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the disclosed subject matter described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present disclosed subject matter only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the disclosed subject matter. In this regard, no attempt is made to show structural details of the disclosed subject matter in more detail than is necessary for a fundamental understanding of the disclosed subject matter, the description taken with the drawings making apparent to those skilled in the art how the several forms of the disclosed subject matter may be embodied in practice. In the drawings:

FIG. 1 shows a block diagram of a configuration of a multi cascade cooling system, in accordance with some exemplary embodiments of the disclosed subject matter;

FIG. 2 shows a block diagram of another configuration of the multi cascade cooling system, in accordance with some exemplary embodiments of the disclosed subject matter;

FIG. 3 shows a block diagram of yet another configuration of the multi cascade cooling system, in accordance with some exemplary embodiments of the disclosed subject matter;

FIG. 4 shows a block diagram of yet another configuration of the multi cascade cooling system, in accordance with some exemplary embodiments of the disclosed subject matter; and

FIG. 5 depicts a P-H diagram of the multi cascade cooling system, in accordance with some exemplary embodiments of the disclosed subject matter.

DETAILED DESCRIPTION

Before explaining at least one embodiment of the disclosed subject matter in detail, it is to be understood that the disclosed subject matter is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The disclosed subject matter is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. The drawings are generally not to scale. For clarity, non-essential elements were omitted from some of the drawings.

One technical objective of the present disclosure is improving energy efficiency of cooling systems by cascading at least one heat exchanger between the condenser and the evaporator of a commercially available cooling system. In some exemplary embodiments, the heat exchanger may be added to the cooling system. The heat exchanger may utilize residual fluids for absorbing heat from the refrigerant that flows between a condenser and an evaporator of the commercially available system. One technical effect of utilizing the disclosed subject matter is significantly reducing energy consumption by lowering the refrigerant temperature with the heat exchanger.

Another technical problem dealt with by the disclosed subject matter is utilizing the availability of residual fluids, such as steam, greywater a combination thereof, or the like. Additionally, addressing the inconstancy and instability nature of residual fluids that may affect the cooling system accuracy, e.g. setpoint temperature and energy consumption.

Another technical solution is to cascade at least one, compressor based, cooling system beyond the heat exchanger for regulating the refrigerant temperature and compensate for the inconstancy of residual fluids fed to the heat exchanger. It should be noted that, loos of residual fluids typically occur at off-pick working hours. Thus, another aspect of the present disclosure is to sustain energy efficiency solutions even if sources of residual fluids are not provided continuously.

One technical effect of utilizing the disclosed subject matter is high efficiency of energy consumption of a refrigerating apparatus. The most important parameters of operation of a refrigerating apparatus with a cascade of two circuits are high precision of control of the parameters of its operation and stability of operation.

Referring now to FIG. 1, showing a block diagram of a first configuration of a multi cascade cooling system 100, in accordance with some exemplary embodiments of the disclosed subject matter. The cooling system may comprise a compressor 101, a condenser 102, a main heat-exchanger 103, an auxiliary heat-exchanger 104, expansion-valve 105, evaporator 107 and temperature sensor 106. In addition, a refrigerant conductor 111 may be used for connecting the listed above refrigerating components in a loop such as the configuration depicted in FIG. 1. In some exemplary embodiments, a coolant refrigerant, such as R22, R410A, R12, R134, or the like, may be flowing in conductor 111 and trough the listed above refrigerating components.

In some exemplary embodiments, the coolant refrigerant flows in a loop from compressor 101 to evaporator 107 in the following order: first condenser 102, 2nd refrigerant circuit of main heat-exchanger 103, 3rd refrigerant circuit of auxiliary heat-exchanger 104 and last expansion-valve 105 before expanding into the evaporator 107. In some exemplary embodiments, the coolant refrigerant flows through the primary circuit 103P of main heat-exchanger 103 and then through the primary circuit 104P of main heat-exchanger 103. The coolant refrigerant may be cooled by fluid flowing via circuit 108 (hereinafter fluid 108) of heat exchanger 103 as well as the fluid flowing in circuit 109 (hereinafter fluid 109) of the auxiliary heat-exchanger 104.

In some exemplary embodiments, the main heat-exchanger 103 may be used as a second step in the cascade system for cooling the coolant refrigerant with fluid 108. Fluid 108 may be provided by a sorption machine (not shown). Additionally, or alternatively, the auxiliary heat-exchanger 104 may be used as a third step in the cascade system for cooling the coolant refrigerant with fluid 109. Fluid 109 may be provided by a commercially available cooling system serving as an auxiliary cooling system (not shown). The sorption machine typically utilizes residual fluid as its source of energy, wherein the energy consumption of both the auxiliary cooling system (ACS) and the sorption machine is substantially lower than the basic system, i.e. system 100 minus both heat exchangers. It will be noted that, the coefficient of performance (COP) of system 100 is dramatically improved due to the utilization to the additional cooling of the coolant refrigerant with fluid 108 that utilized residual energy.

In some exemplary embodiments, the auxiliary heat-exchanger 104 may be used as a third step of cooling in the cascade system. The auxiliary heat-exchanger 104 may be connected after the main heat-exchanger 103 in order to stabilize the coolant refrigerant temperature, due to the volatility of the residual fluid and/or any other absorption material supply. Additionally, the auxiliary heat-exchanger 104 may be used to control cooling to desired temperature, thus used as a regulator. This affects the benefit of the entire system, brings stability to its operations and increases the life span of the compressor and the expansion valve 105. In some exemplary embodiments, auxiliary heat-exchanger 104 may a commercially available cooling system that feed coolant fluid into second circuit 109 in order to regulate the main refrigerant temperature and makeup for temperature loos due to lack of residual heat consistency.

It will be understood that, the double cascade self-regulation system may not require the activation of auxiliary heat-exchanger 104 in the case of increased residual fluid production, where steam, greywater, or the like contributes most of the energy. However, in absence of residual fluid most of the load falls on the condenser 102 and the ACS that provides fluid 109, which will work at apparent temperatures and, consequently, at a much higher COP than the COP of a commercially available machine.

In some exemplary embodiments, the sorption machine may utilize solid absorbent material instead of fluid. Additionally, or alternatively, the sorption machine may be facilitated with a supplementary (spare) heat reservoir (residual) that will feed the machine during absent of residual energy.

In some exemplary embodiments of the disclosed subject matter, the multi cascade cooling system 100, can be utilized in freight transportation vehicles (FTV), such as refrigerated trucks, railroad refrigerator cars, shipping containers, or the like. Refrigerated FTV are used to transport perishable freight at specific temperatures. Cooling system 100 of the present disclosure can also be utilized in cargo vessels for maintaining specific temperatures in bulk transport, such as meat, fish, vegetations hazard material, or the like.

In such FTV exemplary embodiments, cooling system 100 can be similar to the embodiment depicted in FIG. 1, however the main heat-exchanger 103 and the auxiliary heat-exchanger 104 may be powered differently. The main heat-exchanger 103 may be used as a second step in the cascade system for cooling the coolant refrigerant with fluid 108. Fluid 108 may be provided by a sorption machine (not shown). In some exemplary embodiments, a sorption machine utilized in FTV embodiments may differ from the typical stationary sorption machine, due to the source of the residual energy it uses. In FTV embodiments the alternative source of the residual energy can be selected from a group consisting of: radiator fluid of the vehicle engine, oil of the vehicle engine, exhaust fumes, and any combination thereof, or the like.

Additionally, or alternatively, the auxiliary heat-exchanger 104 may be used as a third step in the cascade system for cooling the coolant refrigerant with fluid 109. Fluid 109 may be provided by a commercially available cooling system powered by chargeable auxiliary batteries (not shown). In some exemplary embodiments, the auxiliary batteries can be adapted to be powered by the vehicle alternator and line power, while the vehicle is parking.

The utilization of the sorption machine and the ACS in FTV embodiments significantly lower energy consumption compare to commercially available refrigeration vehicles and thus dramatically improving the COP.

Additional technical effect of utilizing the FTV features of disclosed subject matter is lowering the fuel consumption of the vehicle below a regulation threshold, which gains exemption from biodiesel use.

Referring now to FIG. 2, showing a block diagram of a second configuration of a multi cascade cooling system 200, in accordance with some exemplary embodiments of the disclosed subject matter. The cooling system may comprise refrigerating components such as a compressor 101, a condenser 102, a twofold heat-exchanger 110, an expansion-valve 105, an evaporator 107 and temperature sensor 106. In addition, a refrigerant conductor 111 may be used for connecting the listed above refrigerating components in a loop such as the configuration depicted in FIG. 2. In some exemplary embodiments, a coolant refrigerant (fluid), such as R22, R410A, R12, R134, or the like, may be flowing in conductor 111 and trough the listed above refrigerating components.

In some exemplary embodiments, the refrigerant flows in a loop from compressor 101 to condenser 102 then to the twofold heat-exchanger 110 and then to the expansion-valve 105 before expanding into evaporator 107. In some exemplary embodiments, the refrigerant flow via a primary circuit 110P, of the twofold heat-exchanger 110, can be cooled by a first fluid flowing via a first circuit 108 and a second fluid flowing in a second circuit 109 of the twofold heat-exchanger 110.

In some exemplary embodiments, the first fluid flowing via a first circuit 108, hereinafter fluid 108, may be water or any of the refrigerants, such as described above. Likewise, the second fluid flowing in a second circuit 109, hereinafter fluid 109, may also be either water or any of the refrigerants described above. Fluid 108 can be provided by a commercially available sorption machine (not shown), while fluid 109 may be a typical refrigerant coolant, usually provided by ACS (not shown).

It should be noted that, sorption machines are used for removing heat from the chilled water by utilizing residual energy form steam, exhaust gas, hot water, and any combination thereof, or the like to regenerate the sorption solution. Sorption is a physical and chemical process by which one substance becomes attached to another. It will be noted that the present disclosure can utilize either absorption or adsorption machines. Absorption machines incorporates a substance in one state that changes into a different state, e.g., liquids being absorbed by a solid or gases being absorbed by a liquid. Adsorption machines bond ions and molecules onto the surface of another phase, e.g., reagents adsorbed to a solid catalyst surface. For example, Adsorption machines incorporates solid substance that sorbs fluid coolant and Absorption machines incorporates liquid substance that sorbs gas coolant.

In some exemplary embodiments, either an absorption machine or adsorption machine (not shown) may be used for cooling fluid 108, which subsequently cools the coolant refrigerant (that flow into primary circuit 110P) of the twofold heat-exchanger 110. Therefore, by cascading the twofold heat-exchanger 110 for further cooling the coolant refrigerant, with sorption machine that utilize residual energy, increases the coefficient of performance (COP) of the system.

Additionally, or alternatively, an ACS (not shown), such as, a chiller, or the like may be utilized for regulating fluid 109, which subsequently cools the coolant refrigerant (that flow into primary circuit 110P) of the twofold heat-exchanger 110. It will be appreciated that, fluid 109 may be used for regulating the temperature of coolant refrigerant that flow into primary circuit 110P. In some exemplary embodiments, cooling and regulating the coolant refrigerant may be done simultaneously by fluid 108 and fluid 109 respectively.

The regulation may be required due to the inconstant nature of the residual energy that drives the sorption machine. In some exemplary embodiments, residual energy, such as graywater, steam, or the like may be accumulated during peak hours in order to make-up for off-peak hours, thus sustaining continues supply to the sorption machine. In such embodiments, fluid 109 may be used for regulating the coolant refrigerant temperature in order to compensate for cooling demand and the instability of the fluid 108 temperature. In other exemplary embodiments, fluid 109 may be may also be used to make-up for off-peak hours, in systems that lack residual energy accumulators.

In some exemplary embodiments, cooling the coolant refrigerant of the cascade system can be done in three phases; 1^(st) by compressor 101 with condenser 102; 2^(nd) by fluid 108 and 3^(rd) by fluid 109. It should be noted that, the second circuit 109 of the twofold heat-exchanger 110 may be used for stabilizing the coolant refrigerant temperature, due to the volatility of the residual fluid, which can affect the throughput the sorption machine. The second circuit 109 may also be used to control cooling to desired temperature. This configuration of the cascade cooling system 200 improves the efficiency of the entire system, brings stability to its operations and increases the life-expectancy of the compressor 101 and the expansion valve 105. In some exemplary embodiments, fluid 109 may be provided by a commercially available cooling system that feed coolant fluid 109 to the second circuit 109 in order to regulate the main refrigerant temperature and makeup for temperature loos due to lack of residual heat consistency.

It will be understood that, the double cascade self-regulation system may not require the activation of auxiliary heat-exchanger 104 in the case of increased residual fluid production, where steam, greywater, or the like contributes most of the energy. However, in absence of residual fluid most of the load falls on compressor 101, condenser 102 and the ACS, which will work at apparent temperatures and, consequently, at a much higher COP than the COP of a commercially available machine. It should be noted that, the COP of the cooling cascade system is dramatically improved due to the utilization to the energy accumulation in the residual fluid.

Referring now to FIG. 3, showing a block diagram of a second configuration of a multi cascade cooling system 300, in accordance with some exemplary embodiments of the disclosed subject matter. The cooling system may comprise refrigerating components such as a compressor 101, a condenser 102, a main heat-exchanger 103, an auxiliary heat-exchanger 104, an expansion-valve 105, an evaporator 107 and temperature sensor 106. In addition, a refrigerant conductor 111 may be used for connecting the listed above refrigerating components in a loop such as the configuration depicted in FIG. 3. In some exemplary embodiments, a coolant refrigerant, such as R22, R410A, R12, R134, or the like, may be flowing in conductor 111 and trough the listed above refrigerating components.

In some exemplary embodiments, the coolant refrigerant (fluid) flows in a loop from compressor 101 to condenser 102 then to the main heat-exchanger 103 and then to the expansion-valve 105 before expanding into evaporator 107. The coolant refrigerant flow via a primary circuit 103P, of the main heat-exchanger 103, to expansion valve 105. The coolant refrigerant can be cooled in the main heat-exchanger 103 by fluid 108, provided by a sorption machine (not shown), to circuit 108. In some exemplary embodiments, fluid 108 first enters the auxiliary heat-exchanger 104 for further cooling and temperature regulation purposes. Fluid 108 may be regulated in the auxiliary heat-exchanger 104 by a second fluid flowing in circuit 109 of the auxiliary heat-exchanger 104.

In some exemplary embodiments, the first fluid flowing via circuit 108 (fluid 108) may be water or any of the refrigerants, such as described above. Likewise, the second fluid flowing in a second circuit 109, hereinafter fluid 109, may also be either water or any of the refrigerants described above.

Fluid 108 can be provided by a commercially available sorption machine (not shown), while fluid 109 may be a typical refrigerant coolant, usually provided by ACS (not shown).

It should be noted that, sorption machines are used for removing heat from the chilled water by utilizing residual energy in a form of steam, exhaust gas, hot water, and any combination thereof, or the like to regenerate the sorption solution. Sorption is a physical and chemical process by which one substance becomes attached to another. It is noted that the present disclosure can utilize either absorption or adsorption machines. Absorption machines incorporates a substance in one state that changes into a different state, e.g., liquids being absorbed by a solid or gases being absorbed by a liquid. Adsorption machines bond ions and molecules onto the surface of another phase, e.g., reagents adsorbed to a solid catalyst surface.

In some exemplary embodiments, either an absorption machine or adsorption machine (not shown) may be used for cooling fluid 108, which subsequently cools the coolant refrigerant (that flow into primary circuit 103P) of the main heat-exchanger 103. Therefore, by cascading the main heat-exchanger 103 for further cooling the coolant refrigerant, with sorption machine that utilize residual energy, increases the coefficient of performance (COP) of the system.

Additionally, or alternatively, an ACS (not shown) may be utilized for cooling fluid 109, which cools fluid 108 in the main heat-exchanger 103. It will be appreciated that, fluid 109 may be used for regulating the temperature of fluid 108 due to the inconstant nature of the residual energy that drives the sorption machine. In some exemplary embodiments, residual energy, such as graywater, steam, or the like may be accumulated during peak hours in order to make-up for off-peak hours, thus sustaining continues supply to the sorption machine. In such embodiments, fluid 109 may be used for regulating fluid 108 temperature in order to compensate for cooling demand and the instability of the fluid 108 temperature.

In some exemplary embodiments, cooling the coolant refrigerant of the cascade system can be done in three phases; 1^(st) by compressor 101 with condenser 102; 2^(nd) by fluid 108 and 3^(rd) by fluid 109. It should be noted that, circuit 109 of the heat-exchanger 104 may be used for stabilizing the fluid 108 temperature, due to the volatility of the residual fluid, which can affect the throughput the sorption machine. Circuit 109 may also be used to control cooling to desired temperature. This configuration of the cascade cooling system 300 improves the efficiency entire system, brings stability to its operations and increases the life-expectancy of the compressor and the expansion valve 105. In some exemplary embodiments, fluid 109 may be provided by a commercially available cooling system that feed coolant fluid 109 to the circuit 109 in order to regulate fluid 108 temperature.

It will be understood that, the double cascade self-regulation system may not require the activation of the additional cooling system that provides fluid 108 in the cases of increased residual fluid production, where steam, greywater, or the like contributes most of the energy.

Referring now to FIG. 4, showing a block diagram of a forth configuration of a multi cascade cooling system 400, in accordance with some exemplary embodiments of the disclosed subject matter. It should be noted that, that the following forth configuration of the multi cascade cooling system 400 may be suitable for application where the supply of residual energy is very volatile and may be interrupted frequently.

The cooling system may comprise refrigerating components such as a compressor 101, a condenser 102, a main heat-exchanger 104, an auxiliary heat-exchanger 103, an expansion-valve 105, an evaporator 107 and temperature sensor 106. In addition, a refrigerant conductor 111 may be used for connecting the listed above refrigerating components in a loop such as the configuration depicted in FIG. 4. In some exemplary embodiments, a coolant refrigerant, such as R22, R410A, R12, R134, or the like, may be flowing in conductor 111 and trough the listed above refrigerating components.

In some exemplary embodiments, the coolant refrigerant flows in a loop from compressor 101 to condenser 102 then to the main heat-exchanger 104 and then to the expansion-valve 105 before expanding into evaporator 107. The coolant refrigerant flow via a primary circuit 104P, of the main heat-exchanger 103, to expansion valve 105. The coolant refrigerant can be cooled in the main heat-exchanger 104 by fluid 109, which is provided by ACS (not shown), such as an air condition system, a chiller, or the like. Fluid 109 may be utilized for cooling the coolant refrigerant, that flow into primary circuit 104P of the main heat-exchanger 104. In some exemplary embodiments, fluid 109 may be fed via circuit 109 to the auxiliary heat-exchanger 103, for further cooling purposes, before entering the main heat-exchanger 104. In this exemplary embodiment, the auxiliary heat-exchanger 103 may be used for cooling fluid 109 with fluid 108 provided by a sorption machine (not shown) via circuit 108. It will be appreciated that the sorption machine serves as a supplementary energy source that utilize residual energy that contributes additional cooling to fluid 109. In this configuration additional cooling to fluid 109 is not mandatory for the normal operation of the present disclosure system, however the presence of residual energy dramatically reduces the energy consumption of the cooling system that provides fluid 109, thereby increasing the COP of the overall cascade system. It should be noted that, that the fluid 109 acts as a temperature regulator and its operation may be dictated by cooling demand of setpoint sensor 106 and the presence of the residual energy to the sorption machine.

In some exemplary embodiments, fluid 108 may be water or any of the refrigerants, such as described above. Likewise, fluid 109 flowing in a circuit 109, may also be either water or any of the refrigerants described above. Fluid 108 can be provided by a commercially available sorption machine (not shown), while fluid 109 may be a typical refrigerant coolant, usually provided by ACS (not shown).

It should be noted that, sorption machines are used for removing heat from the chilled water by utilizing residual energy in a form of steam, exhaust gas, hot water, and any combination thereof, or the like to regenerate the sorption solution. Sorption is a physical and chemical process by which one substance becomes attached to another. It is noted that the present disclosure can utilize either absorption or adsorption machines. Absorption machines incorporates a substance in one state that changes into a different state, e.g., liquids being absorbed by a solid or gases being absorbed by a liquid. Adsorption machines bond ions and molecules onto the surface of another phase, e.g., reagents adsorbed to a solid catalyst surface.

In some exemplary embodiments, either an absorption machine or adsorption machine (not shown) may be used for cooling fluid 108, which subsequently cools the coolant refrigerant (that flow into primary circuit 104P) of the main heat-exchanger 104. Therefore, by cascading the main heat-exchanger 103 for further cooling the coolant refrigerant, with sorption machine that utilize residual energy, increases the coefficient of performance (COP) of the system.

Additionally, or alternatively, the additional cooling system (not shown), such as an air condition system, a chiller, or the like may be utilized for cooling fluid 109, which cools the coolant refrigerant. It will be appreciated that, fluid 109 may also be used as a regulator due to the inconstant nature of the residual energy that drives the sorption machine. In some exemplary embodiments, residual energy, such as graywater, steam, or the like may be accumulated during peak hours in order to make-up for off-peak hours, thus sustaining continues supply to the sorption machine. In such embodiments, fluid 108 may be used for further cooling fluid 109 in order to compensate for cooling demand and alleviate the fluid 109 source.

In some exemplary embodiments, cooling the coolant refrigerant of the cascade system can be done in three phases; 1st by compressor 101 with condenser 102; 2nd by fluid 109 and 3rd by fluid 108. This configuration of the cascade cooling system 300 improves the efficiency of entire system, brings stability to its operations and increases the life-expectancy of the compressor and the expansion valve 105.

Referring now to FIG. 5 depicting a P-H diagram of the multi cascade cooling system, in accordance with some exemplary embodiments of the disclosed subject matter. The p-h diagram is a figure with a vertical axis of absolute pressure [p] and a horizontal axis of specific enthalpy [h]. The diagram may be used for determining and evaluating the performance of the present disclosure multi cascade cooling system with respect to commercially available cooling systems. In some exemplary embodiments, vaporous coolant flows out of the evaporator 107 (Point 1) into the compressor 101. Once compressed it has higher pressure and temperature (Point 2). Hot vaporous flows into the condenser 102 where it is cooled down and condensed with minor supercooling (Point 3). In contrast to commercially available cycle, (where a condenser 102 is followed by an expansion valve 105 and a temperature control sensor 6), the present disclosure scheme comprises two additional sequentially connected circuits (103 and 104) for further cooling the coolant refrigerant with fluid 108 and fluid 109. Thus, stretching the cycle (supercooling) to Point 3′ so that the main heat processing load falls onto the circuit 108. Herein, the sorption circuit works under higher temperatures which noticeably rises its COP and allows utilizing low-grade exhaust heat with maximum efficacy. The circuit 109 that is connected after circuit 108 and may be used to control the process of supercooling by way of cooling the base coolant to the pre-set temperature (Point 4′) with high precision. Thereby, increasing the cooling capacity by δQ.

The following, comprising testing data of the exemplary configuration (100) depicted in FIG. 1. The system comprised a basic cooling apparatus, i.e. compressor 101, condenser 102, expansion-valve 105, evaporator 107, temperature sensor 106 connected by refrigerant conductor 111. The refrigerating power of that basic cooling apparatus (with the cascading units) was approximately 350kW. Two cascade units were added to the basic system:

-   -   a. a main heat-exchanger 103 refrigerated by 12 KW solid sorbent         (adsorbent) machine via circuit 108.     -   b. an auxiliary heat-exchanger 104 refrigerated by 15 KW ACS,         having a 4 HP compressor, via circuit 109.     -   c. Thus, a total of 27 KW added by the cascading circuits, which         is less than 8% of the main system.     -   d. coolant refrigerant R22.     -   e. operational temperature in the evaporator 107 is negative         7C°.     -   f. The average temperature of R22 at the outlet of the condenser         102 was 40C°.

The addition of the two cascades allowed bringing down the temperature of the coolant to 18C°, which resulted in 8% increase of the COP. Since the refrigerating load of the apparatus remained stable, the increase of its refrigeration capacity brought about the fans and compressor of the base condenser to stand still, which in turn resulted in a step-up decrease in electricity consumption by 12%. The economy was mostly noticeable at daytime in hot weather when electricity is most expensive.

It should be noted that, the cascading circuits were connected on the hot side of the refrigerating cycle is an effective alternative to designing sorption apparatuses for negative temperatures, both in view of the difficulties of their customization and in view of their low COP.

In the example heat was removed from the base refrigerating circuit under relatively high temperatures (up to +40C°), i.e. Point 3 of FIG. 5, which results in higher COP of both the added circuits and increases the refrigerating capacity (EQ) of the base system substantially close by the value of the supercooling capacity. The margin of enthalpies between Points 3 and 3′ equals the margin of enthalpies between Points 4 and 4′, and is calculated according to the following formula δQ=h_(3,4)-h_(3′,4′), wherein δQ is the refrigerating capacity; h_(3,4) represents values of enthalpy in Points 3 and 4 in the thermodynamic p-h diagram; h_(3′,4′), represents values of enthalpy in Points 3′ and 4′ in the thermodynamic p-h diagram. It should be noted that, the increase of refrigerating capacity δQ takes place alongside minimum consumption of electricity and fosters noticeably the rise of the COP of the base refrigerating circuit.

Such exemplary embodiments demonstrate the efficiency of utilizing low-grade exhaust heat, as well as optimization of operational control of refrigerating apparatuses due to the natural and automatic way of regulation of co-operation of the two added circuits. The choice of the end-temperature of the supercooling process, point 3′ of FIG. 5, is determined by the needs of optimization, and can be reached with high precision owing to the added compression circuit. Sufficient amount of low-potential exhaust heat can be utilized with maximum efficiency, which may bring down electricity consumption by 30%. Reduction of time of operation of the compressors within the base circuit provides for the increase of their performance life, which in turn leads to a decrease in maintenance expenditures.

Although the subject matter has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present subject matter. 

1. A multi cascade cooling system having a refrigerant flowing in refrigerating components, the system comprising: at least one first heat-exchanger configured to receive the refrigerant from a component of the refrigerating components and cooling it with a first fluid provided by a sorption machine; and at least one second heat-exchanger configured to receive the refrigerant from the at least one first heat-exchanger and regulate a temperature of the refrigerant with a second fluid provided by an auxiliary cooler, wherein the refrigerant flows from the at least one second heat-exchanger to another component of the refrigerating components.
 2. The multi cascade cooling system of claim 1, wherein the at least one first heat-exchanger and the at least one second heat-exchanger are integrated into at least one twofold heat-exchanger, and wherein the refrigerant is cooled by the first fluid and regulated by the second fluid in the at least one twofold heat-exchanger simultaneously.
 3. The multi cascade cooling system of claim 1, wherein the at least one second heat-exchanger is configured to regulate another temperature of the first fluid with the second fluid, and wherein the at least one first heat-exchanger is configured to receive the first fluid from the at least one second heat-exchanger for cooling the refrigerant, and wherein the refrigerant flows from the at least one first heat-exchanger to the another component of the refrigerating components.
 4. The multi cascade cooling system of claim 1, wherein the at least one second heat-exchanger is configured to cool the second fluid with the first fluid, wherein the at least one first heat-exchanger is configured to receive a cooled second fluid from the at least one second heat-exchanger for cooling the refrigerant, and wherein the refrigerant flows from the at least one first heat-exchanger to the another component of the refrigerating components.
 5. The multi cascade cooling system of claim 1, wherein the sorption machine is selected from the group consisting of absorption machine; adsorption machine; and any combination thereof.
 6. The multi cascade cooling system of claim 1, wherein the sorption machine is primarily powered by residual energy and wherein the residual energy is selected from the group consisting of gray water; steam; exhaust gas, hot water; and any combination thereof.
 7. The multi cascade cooling system of claim 6, wherein the second fluid is adopted to regulate the temperature of the refrigerant due to inconsistent temperature of the first fluid resulting from volatility of residual energy.
 8. The multi cascade cooling system of claim 1, wherein the component is a condenser and the another component is an expansion-valve.
 9. The multi cascade cooling system of claim 1, wherein the refrigerant is selected from the group consisting of R22; R410A; R12; R134; and any combination thereof.
 10. The multi cascade cooling system of claim 1, wherein the first fluid and the second fluid are selected from the group consisting of water; R22; R410A; R12; R134; and any combination thereof.
 11. A method of operation of the multi cascade cooling system of claim 1, the method comprising: receiving the refrigerant from the component; cooling the refrigerant with the first fluid; regulating the temperature of the refrigerant with the second fluid; and flowing the refrigerant to the another component.
 12. The method of claim 11, wherein said regulating the temperature is regulating the temperature of the first fluid with the second fluid.
 13. The method of claim 11, wherein regulating the temperature of the refrigerant with the second fluid is performed while the first fluid is cooling the second fluid.
 14. The multi cascade cooling system of claim 1, wherein the multi cascade cooling system is installed in a transportation vehicle.
 15. The multi cascade cooling system of claim 14, wherein the sorption machine is powered by residual energy that is selected from the group consisting of radiator fluid of an engine of the vehicle, oil of an engine of the vehicle, exhaust fumes, and any combination thereof.
 16. The multi cascade cooling system of claim 14, wherein the auxiliary cooler is powered by auxiliary batteries of the vehicle. 